Archive for year 2013

7 to 10 inches of Fresh Powder on Mammoth Mtn……More on the way!

Quick update for the Friday-Saturday Storm. Storm still looks very similar to the last system, except it will be colder and the snow lighter…..so it will snow more.   Liquid EQ would be about .5 over Yosemite and probably . 7 or .8 over Mammoth Pass.   The Dweebs still feel at this time that about a foot over the Crest is reasonable with 8 or 9 inches at the main lodge.  In town, 4 to 7 inches so a good plow….

 

Will update amounts again in the morning if necessary………………………………………….

 

The Dweeber………………..:-)

 

Skies dawned clear for the most part over Mammoth Lakes with very cold temperatures.  The low temperatures here at Mammoth Weather.com was 3F degrees with yesterdays high 33.  Temperatures were still the coldest in the upper elevations with a low of -11 at Tuolumne Meadows. That will change as sinking air allows the combination for the cold in the high country to settle into the valleys and radiational cooling to further release heat from the surface.  Expect tonight lows to range from -5 to -15…especially in the colder valleys along the highway 395 corridor.

Today’s high temperature in Mammoth will be cold as modified Arctic Air remains in place. Highs are expected to be in the teens under clear skies.  It is a dry 48 hour forecast.

The next upstream system is currently over the north coast of AK as it rounds the top of the upper high. It is another cold bugger! I like what it is doing as in comes down the coast Friday afternoon. Both 12Z NAM and GFS show the upper jet taking a nice quick Jog to the west off shore to pick up some moisture before in comes south along the central coast. The main VT MAX is depicted a good 175 to 200mi west of the Central Oregon by 00Z Saturday. the jet does become cyclonically curved a bit and so this should generate some good UVM and lift for moisture to get up into the Trop. A large consideration to remember is that yesterdays system’s precip began with temps in the low to mid 30s. This storm will begin as snow in the 20s then cool rapidly into the teens. The Snow to water ratios will be higher, possibly between 15 and 20:1 over the higher elevations. At the moment, the QPF is about .50 for this system over Mammoth. Double that and you get another 8 to 10 inches. if it ends up a little wetter, then we may get a foot. After the system winds down Saturday, it will be followed by another shot of Arctic Air Saturday.  High Temps over the weekend will remain in the 20s with lows in the single digits or below 0.

 

Outlook for Next Week: (Subject to change)

Yesterdays 6 to 10 and 8 to 14 day outlooks were a bit wetter than normal for the Central Sierra. However, I have to say that I can not see where they are getting that from. While it is true that we may get some moisture from the west as the upper ridge collapses early next week over the eastern pacific. Precipitation would be light and isentropically lifted. It looks to me that the trend in the pattern is headed back to the -Phase of the WPO by week 2,  which usually builds a ridge over the eastern pacific and is dry for our area.  However, this time there may be a substantial southern branch of the westerlies undercutting that ridge with the potential for an “AR” event for the pacific NW. How far south the area of confluence goes is dependent upon the depth of the upper low (adjustment wave) that will develop in the Gulf of AK.

More later………………………….

PS:   Big day for mamothweather.com yesterday with 19,059 visitors……

Thanks for your interest everyone!

Dr Howard and the Dweebs………………………………:-)

 

 

 

After a Quick Shot of Light to Moderate Snowfall Tuesday….Modified Arctic Air Invades the High Country Mid Week and Stays into the following Weekend……

Tuesday Evening Update:

Upper trof axis slowed as it moved through Mono County as forecasted.  At the moment the axis is near Lone Pine and will remain over the Owens Valley moving at a snail’s pace through the early morning hours…..reaching Kern County 12Z.  Another ripple moves through in the northerly flow late Wednesday for another round of snow showers from upslope Wednesday night into Thursday AM.

The next important Arctic short wave dives south, and is west along the coast of the pacific NW Thursday night…….700mb RH in the NAM increases rapidly Friday with another round of snow by Friday afternoon and into Saturday.

This particular wave looks interesting. As the upper ridge that currently extends up into Alaska gets pinched off with the break occurring on tonight’s 00z Wednesday NAM at 45 north. If this break occurs in the ridge in this spot at that time, the timing may allow the next short wave to bow way out off the coast and cyclonically really pick up some moisture from the pacific.

However, the 00Z Wed GFS does not pinch off the Upper high at that time. What we get is another cold outside slider with a period of light snowfall Friday night.   So it is too soon to get too excited about another foot yet.

It look like Mammoth Mt picked up about 8 to 12 inches past 15 hours.  Actual tally in the morning from Mammoth Mt.

This particular system is through now….just some snow showers remaining. Do not expect much more than another inch over night.

Cold is now the main message with lows in the low single digits here near the village and -10 to -15 in some of the colder valleys.

Will update in the morning………………

 

PS  I do not remember the models having this much difficulty in handling Pacific energy and the upper flow like it has this fall!!  The spaghetti in the Ensembles is pretty unruly after about 7 days…..

Pretty amazing!

 

8:30am Monday:

I think that were all good on the snowfall prognostication for Tuesday based upon the last discussion.  Tomorrow Tuesday Morning, the Arctic Front is expected to slow as it moves into Mono County and that should give us a bit extra Precip as reflected in the forecast amounts.

Looking down the road there will be several ripples in the flow that are out of the Arctic this week. Any one of them can potentially kick up some snow showers.  There is one short wave in particular, off in the distance with this same pattern, that will come in Friday night worth watching. The Upper jet seems to have a double structure with it, with an apparent part over  Water and the other coupled with it over land.  That is expected to come into Mono County Late Friday night into Saturday. That may be good for several more inches then.

The longer range outlook is greatly subject to change, shows the possibility of the upper high pinching off into a closed upper high over AK, with a significant branch of the westerlies undercutting into the central west coast. If this works out, this may be initially, an isentropic lift precip producer, flowed by some dynamics (UVM) afterwards. This is not a forecast……just looking down the road a week away…..

 

Have a nice day>>>>>>>>>>>>>>

 

Dr Howard and the Dweebs…………………………..:-)

 

10:00 AM Sunday

Everything on track for a very cold week ahead with upper teens and low 20s in town. Even Tuesday’s weather will be cold with high temps near 27F……and that will occur fairly early in the day.

Strong winds will preceed the arctic front with gusts Monday afternoon through the night 30 to 50 MPH in town.

Snowfall:    The new ECMWF QPF is out for Tuesday painting .6 over the crest and there is even a few isolated areas that show .80  Considering how cold the air mass will be and the higher snow to water ratios of at least 15 to 1, it is not unreasonable to expect 5 to 10 inches between 9K and 11,000 feet by Wednesday AM,  and 3 to 5 inches in town. In a few of those isolated spots,  up to a foot could fall.

 

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Well, we could have had a bonanza of snowfall this week if earlier model runs would have stayed consistent. The Current Arctic Low off the coast of Northern BC will instead move into the Pacific NW then become east west orientated across the northern tier states. I have to say that by December, the longer range global models usually do a much better job a week away.

You would expect a  longer range outlook in November to bust, but by late November that’s unusual.  So until the Dweebs see better performance in the longer range, well stick to the short-term and medium range, highlighting that the extended guidance is an outlook rather than something that is more believable. It may be that during this winter, the longer range guidance is one that the Dweebs will use more cautiously.

As far as snow fall goes…light amounts are expected. Will fine tune in the morning….

What we lack in snowfall we will make up in cold weather…..Modified Arctic will invade Tuesday and by Wednesday we will struggle to get out of the teens at 8000 feet. Night time lows will range from the single digits to below zero in some areas. The cold will be prolonged into next weekend. No doubt there will be broke pipes in town……so do what you have to keep the house warm….

 

OutLook:

 

I do see another pattern change during the 2nd week of December….hope its a wet one!

The Dweeber………………………….:-)

Weakening system over the southland may give some snowshowers Thanksgiving day and night….Cold Arctic System makes its way into the Pacific Northwest with Arctic air to Accompany….Snowfall may begin as early as Monday for the Mammoth Area…..

Wednesday AM Update:

The Thanksgiving holiday weather looks mostly cloudy with a slight chance of snow showers both during the day and night. Daytime highs in the 40s and nights in the teens and twenties. The rest of the weekend look party cloudy with little temperature change. Winds will be light……

Last several runs (Tuesday and Wednesday) of the ECMWF and GFS still have quite the powerhouse coming into the pacific northwest early next week. However, an adjustment eastward in the pattern suggests that the upper center is likely to remain over land now and not out over the sea. Nevertheless, plenty of upper jet energy will bow out off shore and then into the Sierra next week, so still a good possibility of significant snowfall.  There are even some signs of a tropical tap later next week.  The Key on all this is this. Recent models run of the GFS has the upper ridge axes at 140west through Alaska.  The ECMWF has the axis about 145 west.  The 140W longitude line for California is Critical. Often times when a long wave highly amped ridge is east of 140W…Storms take a track over land, where by if the ridge axis is west of 140W the track is offshore. The ECMWF is still west of 140W, however, not by much. So a lot will depend upon the eventual placement of the upper ridge when it sets up next week for how much snowfall we get.  The Dweebs have noted that the ECMWF is a better global model when looking out a week then the GFS….

This is an evolving situation in which it will probably not be known, how much snowfall will occur until Sunday for the up coming week. There is no doubt that we will get snowfall. The question is how much and….there is plenty potential for Footage IE 1 to 3 feet over the crest……The Dweebs will not update again until Sunday…….

Have a Great Thanksgiving and Travel Safe!

Dr Howard and the Dweebs……………………………………..:-)